Mouse Physiology Core C is a service core with the purpose of allowing the DDBRTCC Research Base to advance understanding of digestive diseases using mouse models to study physiology and pathophysiology. The Core services are meant to increase the ease and efficiency of studying mouse models, which include transgenic and knock out models including those in which colitis and small intestinal disease occur. In addition, this Core will help our Associate Members who lack experience in using mouse models and have small laboratories, making the labor intensive study of mouse models difficult. The services offered include 1) Advice on establishing and maintaining mouse colonies, including how to breed onto uniform backgrounds; 2) Genotyping by PCR, which includes developing and optimizing primers; 3) Histological services, which include in vivo paraformaldehyde perfusion for tissue fixation, tissue processing, embedding, sectioning (including cryosectioning), some staining including H&E and PAS, advise on IF. A tissue bank of H & E slides of GI organs ofthe mouse models studied by our Research Base are made available for other Core members to use for preliminary studies; 4) Ussing chamber/voltage clamp technology for measuring active ion transport and tight junction permeability and permselectivity is available as is instruction in its use and in calculation ofthe results; 5) Metabolic cages are available as is instruction in help in how to use them for metabolic balance studies, including help in blood, urine, stool collections. Three new services are proposed for addition: 1) An experienced mouse pathologist will help review the GI pathology of mouse models, including basal states of transgenic and knock out mice as well as disease models which affect the GI tract; 2) A cjrtokine multiplex ELISA assay to analyze cytokine protein levels from human and mice; and 3) a FACS technician to perform analyses for our Research Base members who use similar epithelial and immunologic cells, to increase efficiency and quality control.